diff options
Diffstat (limited to 'debian/patches-rt/0003-serial-bcm63xx-Use-uart_prepare_sysrq_char.patch')
| -rw-r--r-- | debian/patches-rt/0003-serial-bcm63xx-Use-uart_prepare_sysrq_char.patch | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/debian/patches-rt/0003-serial-bcm63xx-Use-uart_prepare_sysrq_char.patch b/debian/patches-rt/0003-serial-bcm63xx-Use-uart_prepare_sysrq_char.patch new file mode 100644 index 000000000..580b33688 --- /dev/null +++ b/debian/patches-rt/0003-serial-bcm63xx-Use-uart_prepare_sysrq_char.patch @@ -0,0 +1,78 @@ +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Fri, 1 Mar 2024 22:45:16 +0100 +Subject: [PATCH 03/18] serial: bcm63xx: Use uart_prepare_sysrq_char(). +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.8/older/patches-6.8.2-rt11.tar.xz + +The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT. +The driver splits the locking function into two parts: local_irq_save() and +uart_port_lock() and this breaks PREEMPT_RT. + +Delay handling sysrq until port lock is dropped. +Remove the special case in the console write routine an always use the +complete locking function. + +Link: https://lore.kernel.org/r/20240301215246.891055-4-bigeasy@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + drivers/tty/serial/bcm63xx_uart.c | 24 ++++++++---------------- + 1 file changed, 8 insertions(+), 16 deletions(-) + +--- a/drivers/tty/serial/bcm63xx_uart.c ++++ b/drivers/tty/serial/bcm63xx_uart.c +@@ -285,10 +285,9 @@ static void bcm_uart_do_rx(struct uart_p + flag = TTY_PARITY; + } + +- if (uart_handle_sysrq_char(port, c)) ++ if (uart_prepare_sysrq_char(port, c)) + continue; + +- + if ((cstat & port->ignore_status_mask) == 0) + tty_insert_flip_char(tty_port, c, flag); + +@@ -353,7 +352,7 @@ static irqreturn_t bcm_uart_interrupt(in + estat & UART_EXTINP_DCD_MASK); + } + +- uart_port_unlock(port); ++ uart_unlock_and_check_sysrq(port); + return IRQ_HANDLED; + } + +@@ -703,20 +702,14 @@ static void bcm_console_write(struct con + { + struct uart_port *port; + unsigned long flags; +- int locked; ++ int locked = 1; + + port = &ports[co->index]; + +- local_irq_save(flags); +- if (port->sysrq) { +- /* bcm_uart_interrupt() already took the lock */ +- locked = 0; +- } else if (oops_in_progress) { +- locked = uart_port_trylock(port); +- } else { +- uart_port_lock(port); +- locked = 1; +- } ++ if (oops_in_progress) ++ locked = uart_port_trylock_irqsave(port, &flags); ++ else ++ uart_port_lock_irqsave(port, &flags); + + /* call helper to deal with \r\n */ + uart_console_write(port, s, count, bcm_console_putchar); +@@ -725,8 +718,7 @@ static void bcm_console_write(struct con + wait_for_xmitr(port); + + if (locked) +- uart_port_unlock(port); +- local_irq_restore(flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /* |